This is the second biannual Gordon Research Conference on Chemical and Biochemical Mechanisms in Mutagenesis. The first conference, in 1980, arose out of a need to combine in a single meeting the various research areas central to studying how mutagenesis occurs. The first meeting was attended by about 135 scientists from the United States and 14 from 9 foreign countries. Of the American participants, 10 were from industry, 20 from government agencies and research institutes and the remainder were from academic institutions. All of those present in 1980 indicated a strong interest in continuing this type of meeting. The 1982 conference includes nine discussion sessions, each of which includes 3-5 speakers. Poster sessions will enable all who wish to present work for discussion. Discussion leaders and speakers will include such leading and innovative scientists as T. Sugimura (Japan), K. Kohn (NIH), L. Loeg (Seattle), R. Wells (Madison), D. Grunberger (Columiba), M. Leng (France), J. Fresco (Princeton), F. Becker (Houston), T. Lindahl (Sweden and England), A. Pegg (Hershey, PA), etc. The sessions will cover new chemical reactions, site specific mutagenesis, nuclei acid structure, repair, transcription, transposition, insertions and other timely topics. The impact of such an international and multidiscipline conference should lead to new major contribution toward understanding mutagenesis which is central to both toxicology and carcinogenesis.